guts once again, slotting the 77th-minute grubber for Coen Hess to pounce and snatch a famous 34-30 victory.

To compound Brisbane's plight, they now they face a fight to secure a finals berth as the Broncos brace for a daunting home clash against big guns Souths this Thursday night.

Broncos coach Wayne Bennett believes his side's top-four prospects have been shattered but he scoffed at suggestions Brisbane lack the class and commitment to win the premiership.

Tevita Pangai gave Brisbane some hope. (Ian Hitchcock/Getty Images)

"I don't think we'll make the top four now," he said.

"(To win the premiership), you need to compete and you have to execute. It's not that we haven't done that in games this year.

"Maybe we wanted it too much for Sam (Thaiday). I can't be critical of their effort, I have been critical of their effort in some other games, but not this time."

Brisbane need to finetune several areas to challenge in the playoffs. Their first-half completion rate was woeful at 46 per cent, their defence was shoddy and with the game on the line, they lacked the desperation to repel the Cowboys.

JT just loves kicking the Broncos. (Ian Hitchcock/Getty Images)

Thaiday lamented the never-say-die spirit of his good mate Thurston, Brisbane's grand-final nemesis. His last-play class was a telling lesson for inconsistent Broncos halves Anthony Milford and Kodi Nikorima.

"Why does it end this way?" Thaiday said.

"There were some good moments, but we shot ourselves in the foot, the late-tackle count penalties hurt us.

"The Cowboys are set-play specialists and that's the type of player Thurston is."

Sam Thaiday watches from the sideline in his 300th game. (AAP Image/Michael Chambers)

Skipper Darius Boyd personified the ineptitude. His dropped ball on a basic kick return in the 18th minute spewed into the arms of Jason Taumalolo, who scored the easiest try of his career for a shock 14-2 lead.

After the break, Brisbane had seemingly done enough when Korbin Sims (54th) and Pangai Jr (58th) crossed in the space of four minutes, but Thurston had the last laugh … yet again.